Record event if GSLB references cannot be resolved (#1769)

In the [PR](#1672 (review)) where the istio ingress integration was introduced, it was suggested to record events if GSLB references cannot be resolved. The controller was already generating logs, but an event would help the users debugging using `kubectl describe`.
This is a new feature that was not yet present in K8GB. Therefore, to implement it we need to fetch an EventRecorder and grant the controller the appropriate permissions. The error messages were also adapted and currently look like:
```
[k3d-test-gslb2|test-gslb] ➜ k describe gslb roundrobin-ingress-broken
...
Events:
  Type     Reason          Age                From             Message
  ----     ------          ----               ----             -------
  Warning  ReconcileError  2s (x12 over 12s)  gslb-controller  error resolving references (APIVersion:networking.k8s.io/v1, Kind:Degress not supported)
```
```
[k3d-test-gslb2|test-gslb] ➜ k get events
LAST SEEN   TYPE      REASON           OBJECT                           MESSAGE
5s          Warning   ReconcileError   gslb/roundrobin-ingress-broken   error resolving references (APIVersion:networking.k8s.io/v1, Kind:Degress not supported)
```

The controller also logs a message (this was already the case before this PR):
```
2024-10-31T16:47:29Z ERR github.com/k8gb-io/k8gb/controllers/logging/logr.go:72 > events: Reconciler error {"Gslb":"test-gslb/roundrobin-ingress-broken","controller":"gslb","controllerGroup":"k8gb.absa.oss","controllerKind":"Gslb","name":"roundrobin-ingress-broken","namespace":"test-gslb","reconcileID":"2a6a4ad5-96f6-4ee6-8c04-28de0016fc57"} error="error resolving references (APIVersion:networking.k8s.io/v1, Kind:Degress not supported)"
```

There are many other situations where we can generate events, but they won't be included in this PR to avoid bloating it.

[Documentation about events using kubebuilder](https://book-v1.book.kubebuilder.io/beyond_basics/creating_events)

---

This PR also upgrades the golinter since the old version was not compatible with my local go version. Upon upgrading I also resolved the following warning:
```
WARN The linter 'exportloopref' is deprecated (since v1.60.2) due to: Since Go1.22 (loopvar) this linter is no longer relevant. Replaced by copyloopvar.
```

Signed-off-by: Andre Aguas <andre.aguas@protonmail.com>

.golangci.yaml

@@ -23,7 +23,7 @@ linters:
     - unused
     - depguard
     - dogsled
-    - exportloopref
+    - copyloopvar
     - goconst
     - goprintffuncname
     - nolintlint

Makefile

@@ -46,7 +46,7 @@ LOG_FORMAT ?= simple
 LOG_LEVEL ?= debug
 CONTROLLER_GEN_VERSION  ?= v0.15.0
 GOLIC_VERSION  ?= v0.7.2
-GOLANGCI_VERSION ?= v1.59.1
+GOLANGCI_VERSION ?= v1.60.3
 POD_NAMESPACE ?= k8gb
 CLUSTER_GEO_TAG ?= eu
 EXT_GSLB_CLUSTERS_GEO_TAGS ?= us

chart/k8gb/templates/role.yaml

@@ -7,6 +7,13 @@ metadata:
   labels:
 {{ include "chart.labels" . | indent 4  }}
 rules:
+- apiGroups:
+  - ""
+  resources:
+  - events
+  verbs:
+  - create
+  - patch
 - apiGroups:
   - ""
   resources:

controllers/gslb_controller_reconciliation.go

@@ -28,14 +28,18 @@ import (
 	"github.com/k8gb-io/k8gb/controllers/providers/metrics"
 	"github.com/k8gb-io/k8gb/controllers/refresolver"
 
+	"errors"
+
 	k8gbv1beta1 "github.com/k8gb-io/k8gb/api/v1beta1"
 	"github.com/k8gb-io/k8gb/controllers/depresolver"
 	"github.com/k8gb-io/k8gb/controllers/logging"
 	"github.com/k8gb-io/k8gb/controllers/providers/dns"
 	"go.opentelemetry.io/otel/codes"
 	"go.opentelemetry.io/otel/trace"
-	"k8s.io/apimachinery/pkg/api/errors"
+	corev1 "k8s.io/api/core/v1"
+	k8serrors "k8s.io/apimachinery/pkg/api/errors"
 	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/client-go/tools/record"
 	ctrl "sigs.k8s.io/controller-runtime"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 )
@@ -47,6 +51,7 @@ type GslbReconciler struct {
 	Config      *depresolver.Config
 	DepResolver depresolver.GslbResolver
 	DNSProvider dns.Provider
+	Recorder    record.EventRecorder
 	Tracer      trace.Tracer
 }
 
@@ -66,6 +71,7 @@ var m = metrics.Metrics()
 
 // +kubebuilder:rbac:groups=k8gb.absa.oss,resources=gslbs,verbs=get;list;watch;create;update;patch;delete
 // +kubebuilder:rbac:groups=k8gb.absa.oss,resources=gslbs/status,verbs=get;update;patch
+// +kubebuilder:rbac:groups="",resources=events,verbs=create;patch
 
 // Reconcile runs main reconciliation loop
 func (r *GslbReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
@@ -77,7 +83,7 @@ func (r *GslbReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.
 	gslb := &k8gbv1beta1.Gslb{}
 	err := r.Get(ctx, req.NamespacedName, gslb)
 	if err != nil {
-		if errors.IsNotFound(err) {
+		if k8serrors.IsNotFound(err) {
 			// Request object not found, could have been deleted after reconcile request.
 			// Owned objects are automatically garbage collected. For additional cleanup logic use finalizers.
 			// Return and don't requeue
@@ -161,7 +167,9 @@ func (r *GslbReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.
 	refResolver, err := refresolver.New(gslb, r.Client)
 	if err != nil {
 		m.IncrementError(gslb)
-		return result.RequeueError(fmt.Errorf("error resolving references to the refresolver object (%s)", err))
+		errorMsg := fmt.Sprintf("error resolving references (%s)", err)
+		r.Recorder.Event(gslb, corev1.EventTypeWarning, "ReconcileError", errorMsg)
+		return result.RequeueError(errors.New(errorMsg))
 	}
 	servers, err := refResolver.GetServers()
 	if err != nil {

controllers/gslb_controller_setup.go

@@ -46,6 +46,8 @@ import (
 func (r *GslbReconciler) SetupWithManager(mgr ctrl.Manager) error {
 	// Figure out Gslb resource name to Reconcile when non controlled Name is updated
 
+	r.Recorder = mgr.GetEventRecorderFor("gslb-controller")
+
 	endpointMapHandler := handler.EnqueueRequestsFromMapFunc(
 		func(_ context.Context, a client.Object) []reconcile.Request {
 			gslbList := &k8gbv1beta1.GslbList{}

controllers/refresolver/ingress/ingress.go

@@ -52,7 +52,7 @@ func NewReferenceResolver(gslb *k8gbv1beta1.Gslb, k8sClient client.Client) (*Ref
 	}
 
 	if len(ingressList) != 1 {
-		return nil, fmt.Errorf("exactly one Ingress resource expected but %d were found", len(ingressList))
+		return nil, fmt.Errorf("exactly 1 Ingress resource expected but %d were found", len(ingressList))
 	}
 
 	return &ReferenceResolver{
@@ -93,7 +93,7 @@ func NewEmbeddedResolver(gslb *k8gbv1beta1.Gslb, k8sClient client.Client) (*Refe
 		return nil, err
 	}
 	if ingressEmbedded == nil {
-		return nil, fmt.Errorf("exactly one Ingress resource expected but none was found")
+		return nil, fmt.Errorf("exactly 1 Ingress resource expected but none was found")
 	}
 
 	return &ReferenceResolver{

controllers/refresolver/istiovirtualservice/istiovirtualservice.go

@@ -50,7 +50,7 @@ func NewReferenceResolver(gslb *k8gbv1beta1.Gslb, k8sClient client.Client) (*Ref
 	}
 
 	if len(virtualServiceList) != 1 {
-		return nil, fmt.Errorf("exactly one VirtualService resource expected but %d were found", len(virtualServiceList))
+		return nil, fmt.Errorf("exactly 1 VirtualService resource expected but %d were found", len(virtualServiceList))
 	}
 	virtualService := virtualServiceList[0]
 
@@ -98,7 +98,7 @@ func getGslbVirtualServiceRef(gslb *k8gbv1beta1.Gslb, k8sClient client.Client) (
 // getGateway retrieves the istio gateway referenced by the istio virtual service
 func getGateway(virtualService *istio.VirtualService, k8sClient client.Client) (*istio.Gateway, error) {
 	if len(virtualService.Spec.Gateways) != 1 {
-		return nil, fmt.Errorf("expected exactly one Gateway to be referenced by the VirtualService but %d were found", len(virtualService.Spec.Gateways))
+		return nil, fmt.Errorf("expected exactly 1 Gateway to be referenced by the VirtualService but %d were found", len(virtualService.Spec.Gateways))
 	}
 	gatewayRef := strings.Split(virtualService.Spec.Gateways[0], "/")
 	gatewayNamespace := gatewayRef[0]
@@ -140,7 +140,7 @@ func getLbService(gateway *istio.Gateway, k8sClient client.Client) (*corev1.Serv
 	}
 
 	if len(gatewayServiceList.Items) != 1 {
-		return nil, fmt.Errorf("exactly one Service resource expected but %d were found", len(gatewayServiceList.Items))
+		return nil, fmt.Errorf("exactly 1 Service resource expected but %d were found", len(gatewayServiceList.Items))
 	}
 
 	gatewayService := &gatewayServiceList.Items[0]

controllers/refresolver/refresolver.go

@@ -51,5 +51,5 @@ func New(gslb *k8gbv1beta1.Gslb, k8sClient client.Client) (GslbReferenceResolver
 			return istiovirtualservice.NewReferenceResolver(gslb, k8sClient)
 		}
 	}
-	return nil, fmt.Errorf("incomplete gslb configuration, no ingress found")
+	return nil, fmt.Errorf("APIVersion:%s, Kind:%s not supported", gslb.Spec.ResourceRef.APIVersion, gslb.Spec.ResourceRef.Kind)
 }